#!/bin/bash

# This is a very basic script for developer usage. It has a few known
# limitations (feel free to send patches for these):
# - It is targeted at GIMP usage primarily, hence able to check only
#   Flathub (stable and beta remotes) and GNOME-nightly. Yet some
#   generity is built-in so you can set your own application ID on
#   command line and it should work.
# - It assumes the remotes are named 'flathub', 'flathub-beta' and
#   'gnome-nightly' (for stable, beta and nightly branches respectively)
#   as these are the default names proposed by generated .flatpakref
#   files (SuggestRemoteName field) when first installing software from
#   this repository. So most people will have these remotes registered
#   with these names. Yet it could technically be any name locally and
#   this script is not verifying this.
# - It also assumes the flathub remotes are installed at all (it can't
#   search without them being installed and won't install these for
#   you).
# - It uses bash because I lazily didn't bother making it portable as
#   it's really just a tool for core dev testing. Yet we of course
#   welcome patches if some syntax needs to be rewritten for
#   portability.

install=-1
show_runtime=0
appid=org.gimp.GIMP
remote='flathub'
branch='stable'
prefix='--user'
for var in "$@"
do
  if [[ $var =~ ^-([0-9]+)$ ]]; then
    install=${BASH_REMATCH[1]}
  elif [[ $var = '--beta' ]]; then
    remote='flathub-beta'
    branch='beta'
  elif [[ $var = '--nightly' ]]; then
    remote='gnome-nightly'
    branch='master'
  elif [[ $var = '--system' ]]; then
    prefix='--system'
  elif [[ $var = '--runtime' ]]; then
    show_runtime=1
  elif [[ $var =~ ^- ]]; then
    echo "Usage: ./flathub-releases [--beta] [--system] [-X] [org.example.app]"
    echo
    echo "List all flatpak builds stored on Flathub or GNOME repository."
    echo "The builds for org.gimp.GIMP are looked up by default unless"
    echo "you provide explicitly another AppStream ID."
    echo
    echo "Adding a -X number as option install the numbered release"
    echo "instead of listing them."
    echo
    echo "Options:"
    echo
    echo "-0: install the last build."
    echo "-1: install the previous build."
    echo "-2: install the before-previous build (and so on)."
    echo "-[0-9]+: and so on..."
    echo
    echo "--beta:    list or install a beta release"
    echo "--nightly: list or install a nightly release"
    echo
    echo "--runtime: list or install runtimes (can be associated with --beta and --nightly)"
    echo
    echo "--system:  install as system flatpak (default to user install)"
    echo
    echo "Examples:"
    echo
    echo "* List all beta flatpak builds:"
    echo "    flathub-releases --beta"
    echo "* Install 2-build old beta flatpak:"
    echo "*   flathub-releases --beta -2"
    echo "* Install the latest beta flatpak:"
    echo "*   flathub-releases --beta -0"
    echo "* List all builds of the runtime used by the beta flatpak:"
    echo "*   flathub-releases --beta --runtime"
    echo "* Install the previous runtime build to be used by the beta flatpak:"
    echo "*   flathub-releases --beta --runtime -1"
    exit 1
  else
    appid=$var
  fi
done

package_info_cmd="flatpak remote-info $remote $appid"
package_info=`$package_info_cmd 2>&1`
got_info="$?"
commit_prefix="app"
if [ "$got_info" -ne 0 ]; then
  # By default flatpak will just use either the user or system install
  # depending on what it finds. Funnily the command may fail if the
  # remote is found not 0 or 1 but 2 times (both on user and system).
  # Normally it would interactively ask to choose, but in this specific
  # non-interactive case, it would just silently fail instead. So let's
  # make a second try on user-installed remote (totally arbitrary
  # choice).
  user_system="--user"
  package_info_cmd="flatpak remote-info $user_system $remote $appid"
  package_info=`$package_info_cmd 2>&1`
  got_info="$?"
fi
if [ "$got_info" -ne 0 ]; then
  echo "Flathub query failed with the following error: $package_info"
  exit 2
elif [ "$show_runtime" -eq 1 ]; then
  # With the special --runtime option, we list the associated runtime instead of
  # the application.
  runtime=`echo "$package_info" | grep Runtime: |sed 's/^ *Runtime: //'`
  appid=$runtime
  # The beta runtime is in the stable repository.
  if [[ $branch = 'beta' ]]; then
    remote='flathub'
  fi
  package_info_cmd="flatpak remote-info $user_system $remote $appid//$branch"

  package_info=`$package_info_cmd 2>&1`
  got_info="$?"

  if [ "$got_info" -ne 0 ]; then
    if [ -z "$user_system" ]; then
      # Do the user/system dance again. Previously we were doing this about the
      # main package, not its runtime.
      user_system="--user"
      package_info_cmd="flatpak remote-info $user_system $remote $appid//$branch"
      package_info=`$package_info_cmd 2>&1`
      got_info="$?"
    fi
    if [ "$got_info" -ne 0 ]; then
      echo "Flathub query failed with the following error: $package_info"
      exit 2
    fi
  fi

  commit_prefix="runtime"
fi

release_number=0
install_commit=
while [ "$got_info" -eq 0 ]
do
  release_date=`echo "$package_info" | grep Date: |sed 's/^ *Date: //'`
  release_commit=`echo "$package_info" | grep Commit: |sed 's/^ *Commit: //'`
  release_subject=`echo "$package_info" | grep Subject: |sed 's/^ *Subject: //'`
  if [ "$install" -eq -1 ]; then
    # In non-install mode, just list the whole release.
    printf "%2d: %s [%s] - $commit_prefix-commit: %s\n" $release_number "$release_subject" "$release_date" "$release_commit"
  elif [ "$install" -eq "$release_number" ]; then
    install_commit=$release_commit
    break
  fi

  parent_commit=`echo "$package_info" | grep Parent: |sed 's/^ *Parent: //'`
  release_number=$(( $release_number + 1 ))

  package_info=`$package_info_cmd --commit $parent_commit 2>&1`
  got_info="$?"
done

if [ "$install" -ne -1 ]; then
  if [ -n "$install_commit" ]; then
    # Flatpak doesn't have a way to install directly a commit, but we
    # can install then update. This will work whether the flatpak is
    # already installed or not.

    echo "[1/2] Installing $appid"
    flatpak install -y $prefix $remote $appid//$branch

    echo "[2/2] Updating to commit '$install_commit' ($release_number's previous build)"
    flatpak update -y $prefix --commit=$install_commit $appid//$branch

    if [ "$?" -eq 0 ]; then
      echo "Build $release_number released on $release_date was installed."
      echo "Build subject: $release_subject"
      echo "Build commit on $remote: $release_commit"
    else
      echo "Failure to install build $release_number released on $release_date."
      exit 2
    fi
  else
    echo "There was no $release_number's build to install. Aborting."
    exit 1
  fi
fi

exit 0
